On April 27, 2012, the first subject completed their follow-up interview in our ongoing relapse study of MDMA-assisted psychotherapy for PTSD in two or three subjects whose symptoms returned several years after participating in our completed U.S. proof of principle study. The co-therapists for this study are Dr. Michael Mithoefer and Annie Mithoefer, B.S.N., who also conducted the original proof of principle study. The two-month follow-up evaluation revealed that a single additional open-label MDMA-assisted psychotherapy session was sufficient to reduce this subject’s score on the Clinician-Administered PTSD Scale (CAPS) below the diagnostic cutoff for PTSD. The results suggest that people who relapse after the initial series of treatments as a result of additional life stressors could benefit substantially from a single additional MDMA-assisted psychotherapy session.